FuelLabs/fuels-ts · error · FuelError

DECODE_ERROR

DECODE_ERROR

Error message

Invalid raw slice data size.

What it means

Thrown by RawSliceCoder.decode() when the data buffer is shorter than WORD_SIZE (8 bytes). The raw slice encoding begins with an 8-byte u64 big-endian length prefix, so any payload smaller than 8 bytes cannot contain even the length header.

Source

Thrown at packages/abi-coder/src/encoding/coders/RawSliceCoder.ts:30

  constructor() {
    super('raw untyped slice', 'raw untyped slice', WORD_SIZE);
  }

  encode(value: number[]): Uint8Array {
    if (!Array.isArray(value)) {
      throw new FuelError(ErrorCode.ENCODE_ERROR, `Expected array value.`);
    }

    const internalCoder = new ArrayCoder(new NumberCoder('u8'), value.length);
    const bytes = internalCoder.encode(value);
    const lengthBytes = new BigNumberCoder('u64').encode(bytes.length);

    return new Uint8Array([...lengthBytes, ...bytes]);
  }

  decode(data: Uint8Array, offset: number): [number[], number] {
    if (data.length < this.encodedLength) {
      throw new FuelError(ErrorCode.DECODE_ERROR, `Invalid raw slice data size.`);
    }

    const offsetAndLength = offset + WORD_SIZE;
    const lengthBytes = data.slice(offset, offsetAndLength);
    const length = bn(new BigNumberCoder('u64').decode(lengthBytes, 0)[0]).toNumber();
    const dataBytes = data.slice(offsetAndLength, offsetAndLength + length);

    if (dataBytes.length !== length) {
      throw new FuelError(ErrorCode.DECODE_ERROR, `Invalid raw slice byte data size.`);
    }

    const internalCoder = new ArrayCoder(new NumberCoder('u8'), length);
    const [decodedValue] = internalCoder.decode(dataBytes, 0);

    return [decodedValue, offsetAndLength + length];
  }
}

View on GitHub (pinned to b3f37c91ac)

Solutions

1. Verify data.length >= 8 (WORD_SIZE) before calling decode().
2. Ensure the data was produced by a compatible encoder or Sway ABI.
3. Check for ABI mismatches if data consistently fails this check.

Example fix

// before
rawSliceCoder.decode(new Uint8Array([1, 2, 3]), 0); // throws DECODE_ERROR

// after
const WORD_SIZE = 8;
if (data.length < WORD_SIZE) {
  throw new Error('Data too short for raw slice decode');
}
rawSliceCoder.decode(data, 0);

const WORD_SIZE = 8;
function canDecodeRawSlice(data: Uint8Array): boolean {
  return data.length >= WORD_SIZE;
}

When it happens

Trigger: Passing a byte array with fewer than 8 bytes to decode(). Receiving a truncated or empty ABI-encoded raw slice from an RPC call. Using the wrong coder for the data format.

Common situations: Malformed RPC response data. Buffer truncation during network transmission. ABI version mismatch producing differently sized payloads.

Related errors

• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR

AI-assisted analysis of FuelLabs/fuels-ts@b3f37c91ac (2026-08-12). Data as JSON: /api/errors/3ce87c67a381db6b. Report an issue: GitHub.